WHAT IS A ROTARY HAMMER?

The hammer performs several actions simultaneously. It both advances the drill bit into the material being drilled and turns the drill bit like a drill. The piston system and air pressure drive the drill into concrete or masonry materials. This combination is more robust than a hammer drill. Actual strikes are also less frequent.

Hammers use SDS-Plus or SDS-Max bits. Hilti has alternate names for these, but they are completely compatible. These bits slide and lock into the hammer collet and do not require a collet key or any other tools to insert or remove. You can also find spline bits, but they are less common and more or less outdated.

Electric hammers generally dwarf hammer drills in size and are not shaped like a typical drill bit. You also never use a hammer to drive fasteners, a hammer drill does double duty.